--- a/xpcom/io/nsLocalFileUnix.cpp
+++ b/xpcom/io/nsLocalFileUnix.cpp
@@ -74,6 +74,10 @@
 #include "nsTraceRefcnt.h"
 #include "nsHashKeys.h"
 
+#ifndef BLOCK_SIZE
+#define BLOCK_SIZE  1024
+#endif
+
 using namespace mozilla;
 
 #define ENSURE_STAT_CACHE()                     \
